Steering apparatus



Patented Feb. 2, 1954 UNITED SITES OFFICE STEERING APPARATUS Application June 12, 1953, Serial No. 361,189

6 Claims.

This invention relates to improvements in hydraulic telemotor mechanisms and in steering systems employing such mechanisms.

A principal object of the invention. is to provide a hydraulic telemotor mechanism of improved characteristics, the use of which for remote control purposes confers upon the asociated steering system improved characteristics as hereinafter set forth.

More specifically an object of the invention is to provide a telemotor system that will aiford finger-tip steering, that is to say a minimum torque at the steering wheel.

Another object of the invention is to provide a telemotor mechanism which avoids necessity for use of electrical solenoids, switches, equalizing valves, and special devices for maintaining a synchronized relationship between the transmitter and receiver elements of the telemotor mechanism.

Still another object of the invention is to provide a telemotor mechanism which is immune to the effects of leakage or of introduction of air into thesystem.

A further object of the invention is to provide a telemotor mechanism which affords a continuous synchronized relationship with an independent and alternative electrical steering control with which the system may be associated, whereby the system may be switched from the normal manual control to the alternative control or vice versa at any time and without reference to the actual or relative positions of the transmitter and receiver elements of the mechanism.

Still another object of the invention is to provide a hydraulic telemotor mechanism wherein means is provided for continuously indicating the position of the actuated member of the receiver element as well as the position of the With reference to the drawing, the telemotor mechanism therein illustrated comprises essentially a rotary pump l of the positive reversible discharge type; and an hydraulic motor 2 which consists of a plunger 3 having reciprocatory movement over a predetermined limited path, as hereinafter described, and which in accordance with the invention is free for unrestrained movement over the full extent of said path under action of hydraulic pressure imposed by the pump. In the present instance the opposite ends of the plunger 3 are operatively associated with cylinders 4 and 5 respectively, the outer ends of these cylinders being connected by pipes 6 and 1 respectively with opposite sides of the pump I. In normal operation, therefore, the linear movements of the plunger 3 will be directly proportional to the angular movements of the pump I and the direction of movement of the plunger will be determined by the direction of rotation of the pump.

Means is provided for operatively connecting the pump I with a steering member which in the present instance takes the form of a conventional wheel 8. The hub of this wheel is attached to a shaft 9 which carries a bevel gear II, and this gear is connected through a bevel pinion I 2 with a spur gear I3 which in turn meshes with a spur pinion I4 at the upper end of the shaft l5 of pump l. The plunger 3 has a cross head l6 which in the present instance is connected through a link IT with one end of a lever I8 mounted on a fixed pivot l9. As here inafter set forth this lever constitutes an element of a transmission by means of which the plunger 3 is operatively connected to steering apparatus hereinafter described. The travel of the piston 3 is limited in the present instance by a pair of stops 2! and '22 which are adjustable longitudinally of a supporting rod 23 and which are located in the path of the cross head It so as to form abutments for the latter. Also in accordance with the invention, the cross head it is provided with a rack 24 which meshes with a pinion 25 on a shaft 26, this shaft carrying also a bevel gear 2! which meshes with a pinion 28 on the shaft of a synchronous electric motor 29. This motor is operatively connected with a corresponding motor 3! which is connected through a pinion 32 and a gear 33 with the pointer 34 of an indicator 35 located adjacent to the wheel 8 so as to be visible to the steersman. This device aifords the steersman a continuous indication of the position of the plunger 3 in its pathof travel between the stops 2|.

The shaft 9 is also connected by gears 36 and 31 with a shaft 33 which, through the medium draulic medium. Each of the pipes 33 and 54 contains a pressure relief valve, Alt and 41 respectively, these valves permitting movementmf liquid from the pipes and i to the tank under predetermined excessive pressures in the hydraulic system. Each of theipipesi'fi and Tris'also connected to the tank 45 by'a pipetBandd'Qrespectively, each of which contains a replenishing check valve 51 and 52 and a vent:'cockl53;and:5fl respectively. The latter cocks ailord a meansfor bleeding the hydraulic system of accumulations of air when filling and purging the hydraulic system, and the replenishing check valves '5 l and 52 provide forautomatic trans'ferof liquid "from-the tan'k45-to the system as required.

'The pipes 6 and 'l are also connected :by a valve-controlled bypass 55 through "which the pump 1 'may be short circuited to'permit freeflow of fluid throughthe pipes '5 and? independently "ofthe'pump. When the operation of the system isby'way of the Wheel 8 the valv 5 of this'bypass 'will'be closed, but ifit be desired 'to operate the steering apparatus by the aforesaid independent electrical'steering control, provision for which is made as hereinafter'described, the valve 56 will happened so as 'to permit free movements of the plunger -3 in .the pistons 5 and 5 under operation of the said independent controls.

With reference'to' Figure2 it will be notedthat in the present instance-the lever Wis-connected by a link 51 with a floating lever Sdpivotally supported on a pump 'control rod-59. This rodconstitutes a means fora'djusting the direction and rate of discharge of ap'ositive displacement pump 61, preferably "of the type disclosed in -U.'S.Patent Number l;932;892, this pump being driven continuously by an-electric motor62. 'The'pump 61 is connected through pipes 63 andt l with the outer-ends of a pair'of cylinders65 and65 wliich constitute elements of a reciprocatoryhydraulic motor, this motor comprising a plunger 6?, 'the ends of which-are opera'tively associated respectively with the cylinders '65 andfiB. The plunger '61 carries a cross head 58 which is connected through an armfis with thesteeringpost' ll of a rudder l2. lTheconnection between the piston randrudder is such that a movement of the pisztoninrone direction will'cause the rudder'tomove in an opposite direction toward one of the exltreme positions indicated in broken lines, a re- .verseimovement of the piston efiecting 'a move- :ment oftherudder in the opposite direction. The ffloating lever 58 is alsoiconnected throug'ha link 13,:alever 14,'anda second link 15 with the cross hea d .63, this connectionproviding for the usual follow up which with any adjustment of the pump control rod 59 'resultingfrom actuation of the lever =lt will tend to return the rod to its original position' therebyinterrupting the operation of "the pump 61 which wasinitiated by the original'a'djustment through the lever It. The mode 'of operation of steering apparatus of this ch-aracteris well understood in the art.

It is'to be understood that the hydraulic 'telemotor in accordance with the "invention is not limited in its applications to steering "apparatus .of the elec'troehydraulic type or to follow up j motion of the steering wheel.

mechanisms of the floating lever type described in the foregoing, but is also applicable to steering apparatus and follow up mechanisms of other constructions, well understood in the art, having available means of mechanical connection to the input end of the follow up mechanism.

With further reference to "Figure Z it will be noted. that the floating lever 58 is connected through a link 16 with a rack 11, this rack meshing with a pinion 18 on the shaft of a synchronous motor constituting an element of an independent electric control device indicated generally by the reference numeral 79. As previously set "forth the pump 6! may b actuated selectively from the wheel 8, through the asso- "ciated telemotor'mechanism, and through the independent-electrical control device I9. When the telemotor is employed, the bypass 55 will be closed by'the'valve 55 to render the hydraulic telemotor system operative. When the independent control 19 is employed'the valve :5fiwill be opened so that'pistonifi will be free to move with adjustments of the lever 18 by the'said independent control. 'The independent control '19 is such that it may remain permanently geared'through tth'e rack 1:7 and pinion 78 with the'floatingleverr5ii so that the synchronized relationship between the control device '19 and the rudder 1:2 remains constant and unchanged.

There are several material advantages .in a telemotor mechanism :of this :kind as compared with those employingitransmitters :of "the reciprocating plunger type. :Regardlessiof whether the telemotor :transmitter employs reciprocating plungers or a rotary pump, the motion "of the plungers of 'the;receiver :and of the :steering -:.con-

'trol mechanism connected" thereto is, .in the absence of leaks, bypassing, or air inclusions :in "the hydraulic circuit, proportionate to the angul r The receiverzunit aft is therefore synchronized with :the transmitteriunit forward, 'andian indicator geared toithe steering "wheel shaft will report in :effect, the position of the receiver plungers, and alsozthe positionto whichithe'rudder is moved 'asthe's'teering "gear. responds to its control "mechanism. 'Inequality of liquid between "the two :sides :of the "hydraulic-system, however, due to .leaks, bypassing, or air .in the system, resultsqin loss of :synchronism between transmitter and receiver. Since plunger type transmitters the :rotation of the :steering wheel'is limited "by'the travel :of the plungersof thetransmitter'in their cylinders it is necessary with this type of transmitter "to provid equalizing and re-centering features to restore the transmitter and :receiver to syn'chronism, both :in order to maintain accuracy of indication .and to :prevent continued orprogressive limitation of Jtravelof the receiver.

With some types of telemotors employing plunger type 'transmittters for example equalization and replenishing are accomplished byautomatically opening both sides of the hydraulic system to an atmospheric tank when the transmitter is at, or very close to the "amidShip position, whereupon springs on the receiver 'recenter the receiver plungers in their amidship position. While these springs thus perform an important function for this type of "telemotor, they require an efiort on the Wheel to compress them, which effort increasesias the helm-angle is increased. Another plunger transmitter type of telemotor uses a series of electrical limit switches in control of a solenoid :operated valve to'resynchron'ize the transmitter and receiver.

In the rotary pump type telemotor, of the type forming the subject of the present invention, the rotation of the wheel is not limited by the travel of transmitter plungers in their cylinders, and the repeat-back indicator shows the position of the receiver regardless of the position of the steering wheel relative to that of the receiver. There is no necessity therefore for equalizing and re-centering. In the event of small leaks or air inclusions in the system during operation, it is only necessary to turn the steering wheel an additional amount until the indicator shows the desired rudder position.

The pressure relief valves and replenishing check valves for both sides of the system, headed into the atmospheric tank 45, afford protection against thermal expansion and against excessive wheel effort in the event the telemotor receiver is driven hard against its stops or the connected control mechanism is jammed. Pressure relief and liquid replenishing are accomplished without loss of indication.

It will be noted also that, except during periods of pressure relief and replenishing, the hydraulic system is a closed circuit, afiording sensitive response to the wheel in all positions and eliminating the periods of dead helm (in which movement of the wheel does not produce movement of the receiver plungers) encountered when plunger-type transmittters are opened to atmosphere or are bypassed for equalizing and re-centering. As compared with telemotors employing re-centering springs, the wheel effort required by the rotary pump type telemotor of the present invention is low, and the operating pressures in the hydraulic system are correspondingly low.

We claim:

1. Steering apparatus comprising in combination a hydraulic steering motor, a positive displacement pump connected to said motor, control means for the pump, a manual steering member, a rotary pump having a driving connection with said member, a second hydraulic motor operatively connected to the said pump control means as an actuator for the latter and connected to the rotary pump for transmitting hydraulically to said control means the movements of the said steering member, means for limiting the travel of said second motor, and said second motor except for its connection with said control means being free for unrestrained movement over the full extent of said travel.

2. Steering apparatus according to claim 1 including a second and independent actuator for the pump control means in permanent connection with the latter.

3. Steering apparatus according to claim 2 wherein means is provided for short circuiting the rotary pump so as to afiord free movements of the second motor independently of the rotary pump.

4. Steering apparatus comprising in combination power-driven means for imparting rotative motion to a steering device, follow up control means for said power-driven means, a manual steering member, a rotary pump having a driving connection with said member, a hydraulic motor operatively connected to the said follow up control means as an actuator for the latter and connected to the rotary pump for transmitting hydraulically to said follow up control means the movements of the said steering member, means for limiting the travel of the said hydraulic motor, and said hydraulic motor except for its connection with said control means being free for unrestrained movement over the full extent of said travel.

5. Steering apparatus according to claim 4 including a second and independent actuator for the follow up control means in permanent connection with the latter.

6. Steering apparatus according to claim 5 wherein means is provided for short circuiting the rotary pump so as to afford free movements of the hydraulic motor independently of the pump.

AUGUST W. KUMPF. THOMAS A. HARVEY.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,429,101 Ross Sept. 12, 1922 1,725,489 Stratton Aug. 20, 1929 2,185,277 Stelzer Jan. 2, 1940 2,348,323 Binder May 9, 1944 

